2017.01.20 20:07 "Re: [Tiff] Fwd: TIFF image displayed upside down", by Bob Friesenhahn
So TIFFRGBAImageGet will always reorient the image and it does it the "windows bitmap" way.
thank you, i know why :)
now, how can I use libtiff to display it correctly? i've tried several things, without success
If the image is oriented in strips then you could use scanline-level access with TIFFReadScanline(). This would mean that you need to decode (unpack) the scanlines yourself. This is much more efficient than TIFFRGBAImageGet() but it is also quite a lot more work.
If you were able to run a utility on your target, then you could use 'tiffcrop' to rotate the image.
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/